Dan Kaminsky was an 11-year-old computer whiz working all night behind his bedroom door in St. Francis Wood when his mother, Trudy Maurer, got a phone call alerting her to what her son was up to.

© Angie Roberts

Daniel Kaminsky at a computer convention in 2000.

The call came from the internet administrator of the Western U.S., warning her that someone in the house was “looking around in places where he should not be looking,” specifically military sites, and that he should stop under threat of seeing the family connection shut down.

Maurer responded with a threat of her own. She took out an ad in The Chronicle saying that “government security is so crappy, even an 11-year-old can break it.” They negotiated a three-day suspension of service, which drove Dan nuts. “He was infuriated that his rights were abrogated,” she said. “At 11 he knew the word abrogated.”

He also knew the word “cybersecurity,” and after that three-day suspension lifted, young Dan went on to prove that he could hack into any system, anywhere. He put that expertise to good use by becoming a preeminent expert in internet security. Kaminsky worked on contract for Microsoft, Google, Cisco and other big technology firms.

Kaminsky died April 23 at his home in San Francisco. The cause of death was diabetic ketoacidosis, said his aunt, Dr. Toby Maurer. He was 42.

“Most people in his profession are nerds,” his mother said, “but Dan was captain of his high school debate team and he could speak to people who knew nothing about cybersecurity in layman terms that they could understand.”

In a 2016 video on hacker history, Kaminsky said: “We made the internet less flammable. … The internet was never designed to be secure. The internet was designed to move pictures of cats. … We didn’t think you’d be moving trillions of dollars on this. What are we going to do? And here’s the answer: Some of us gotta go out and fix it.”

To do so, Kaminsky was perpetually on the road troubleshooting problems on computer networks all over the world. He’d return for a day or two and stay with his mother, then be gone again, sometimes with less than 24 hours’ notice….